1. Field of the Invention
The present invention relates to hand-held sheet metal brakes and, more particularly, to a portable brake system enabling the jaw assemblies to be rotationally repositioned relative to the frame member and which incorporates a hinged a bending member having pivot elements that do not intrude into the working space of the brake system.
2. Description of the Related Art
Conventional brakes typically consist of a fixed lower jaw, a movable upper jaw secured to a "C"-shaped member, and a hinged movable member or apron attached to the fixed lower jaw. A disadvantage found with various conventional hinges involves their orientation with respect to the working space, notably in the fact that the hinge structures protrude above the plane of the fixed lower jaw and the "at-rest" hinged member. This protruding characteristic serves as an obstacle to and typically prevents the feeding of material from the end of the brake.
It is common for brakes, especially lightweight portable brakes built for the siding industry, to include a pair of base rails on which the "C"-shaped members are positioned at longitudinally-spaced intervals. A first member is fixed on the lower arms of the "C"-shaped member and has a clamping surface. A second member having a bending surface is hinged (usually a piano-type) to the first member. An anvil member is provided over the clamping surface and an upper movable jaw is secured between the anvil and the upper arms of the "C"-shaped member. The "C"-shaped member and piano-type hinge allow material that is wider than the brake itself to be worked since it can extend laterally with no impedance from the hinge pins. However, the longitudinally-spaced "C"-shaped members prevent material from being fed from the rear of the brake, except through the space between adjacent ones of the "C"-shaped members. Additionally, this brake configuration does not permit material, particularly preformed material such as ducts and pipes commonly used in the heating, air conditioning and ventilation (HVAC) industry, to be fed into the brake from the end.
There is a current need for equipment in the HVAC industry that can rework existing ductwork at the job site. This task is usually undertaken with hand seamers, which are a plier-like device with two flat plates designed to clamp onto the sheet metal after which a bend is made with an upward or downward motion of the wrist. These bends have disadvantageous rounded corners, especially when working with the heavier gauges of sheet steel. Additionally, the hand seamers typically are limited to approximately six inches in working width and therefore the sheet metal must be sectionally worked in piece-wise fashion across the front edge of the metal piece in six inch increments, such that partial bends are made on the first pass and the remaining bends are made on the second pass. This iterative bending process is clearly time consuming and introduces a degree of inexactness into the process since each bending iteration might not be exactly reproducible relative to the other bends.